Bringing It Home: The 14th annual Community Bankers Symposium by Pamela Kennedy, senior examiner and financial analyst, Mark Ahern, senior examiner, Aaron Berlowe, senior examiner, Jennifer Dollen, examiner, Elizabeth Ewing, lead examiner, Robert Jefferies, senior examiner, William Mark, lead examiner, Jessica Swiatek, examiner, and Scott Verbeke, senior examiner, all of Supervision and Regulation

Northern Polar coastal wetlands contain habitats of great importance to wildlife and human populations. Their distribution is determined by underlying geoecological events and processes. They are characterized by cold climate and the presence of ice (sea ice and permafrost) and are influenced by other biotic and abiotic processes (sedimentation, salinity, tidal action, and freshwater input). Pleistocene ice sheets have molded the landscape, and their retreat and subsequent isostatic uplift have led to continuing postglacial local land emersion. Diversity of Arctic wetland plants and fauna is relatively low and characterized by few, widely distributed species; diversity decreases at higher latitudes. On the Russian Arctic coast, progressive deglaciation has favored northward migration of plants from Atlantic/European sources to western areas and Pacific/American ones to eastern areas. Arctic wetlands are of major importance for waterbirds as breeding and migration areas; they are vulnerable to a wide variety of environmental changes, especially climatic change.

Many species of Arctic breeding geese have increased significantly over the last thirty years (Ogilvie and St. Joseph 1976, CWS, USFWS and Atlantic Flyway Council 1981, Boyd and Pirot 1989, Owen and Black 1991, Fox et al. 1992, Abrahamet al. 1996). In North America, these include lesser snow geese (Anser caerulescens caerulescens), greater snow geese (A. c. atlantica), Ross' Geese (A. rossii), greater white-fronted geese (A. albifrons), and some populations of Canada geese (Branta canadensis), e.g., B.c. interior of the Mississippi Valley Population and B.c. parvipes of the Short Grass Prairie Population. In addition, some temperate breeding Canada geese (B.c. maxima) have also increased (Rusch et al. 1995, Allan et al. 1995). Most increases are the direct or indirect result of human activities; their combined effects represent biomanipulation of goose populations on a massive scale. The mid-continent population of lesser snow geese, for example, now exceeds three million birds, and the population is increasing at a rate of at least 5% per annum (Abraham et al.1996) (Fig. 2.1).

Biogeochemical activity occurs year-round in arctic soils, and previous studies from both alpine and arctic tundra sites have revealed that soil microbial biomass (MB) in the active layer reaches an annual peak in winter, and decreases during or shortly after soil thaw. This decline occurs concurrently with, or is followed by, a peak in soil nutrients that provide an important nutritional resource for plant growth. We documented both intra- and inter-annual MB and nutrient patterns in wet and dry sedge meadows near Churchill, Manitoba, Canada between June 2004 and June 2008. Intensive sampling occurred during the winter-spring transition and soils were analyzed for MB, microbial nitrogen, dissolved organic carbon and nitrogen, and inorganic nitrogen. A consistent seasonal pattern was observed wherein large winter MB pools responded negatively to winter warming event, and decreased steeply during soil thaw, suggesting that soil physical factors drive the observed microbial declines. Nutrient pools showed similar seasonal fluctuations, however a post-thaw nitrogen increase was observed in 2006, but not in other years. Inter-annual patterns were similar between wet and dry sedge meadows, including relatively low peak values of all variables by 2008 in both ecotypes, which could be related to observed hydrological changes. As northern climates continue to change, seasonal biogeochemical events that affect the timing and magnitude of nutrient pulses will be altered, with important implications for primary productivity and ecosystem functioning.

The relative allocation of endogenous- and exogenous-derived nutrients to reproductive investment in Arctic-nesting geese is affected by body size, migration distance, and proximate conditions on the wintering, staging, and breeding grounds prior to clutch initiation. We used delta C-13 and delta N-15 measurements of muscle tissue and egg lipid-free yolk and albumen and delta C-13 analysis of abdominal fat and egg yolk lipids, together with isotopic analyses of foraging plants, to quantify the relative use of endogenous and exogenous reserves in egg production in a breeding population of sub-Arctic Lesser Snow Geese (Chen caerulescens caerulescens) on the Cape Churchill Peninsula, Manitoba, from 2005 to 2008. We used a concentration-dependent, two-isotope, three-source Bayesian (SIAR) mixing model to derive estimates of endogenous reserves to egg macronutrients and a single-isotope (delta C-13), two-source (exogenous vs. endogenous) Bayesian model to estimate the source of lipids to eggs. Endogenous protein contributions to eggs were similar to those found using identical Bayesian analytical methods for the larger-bodied Greater Snow Goose (Chen caerulescens atlantica) breeding in the Canadian High Arctic and were on the order of 30%. However, endogenous lipid contributions were considerably greater for the population of Lesser Snow Geese (mean annual contribution of 55.5% vs. 22.3%). This suggests that advantages of larger body size for transport of body lipid reserves for long distances may be countered by the need to use lipids to fuel migration over greater distances. In addition, feeding opportunities of Greater Snow Geese upon arrival at their more distant breeding sites were likely adequate to offset a shorter breeding season and longer development times for offspring than at lower-latitude sites. Received 6 April 2010, accepted 25 September 2010.

Summary 1. Processes of decomposition occur year‐round in tundra ecosystems and respond quickly to seasonal changes. Characterizing the phenology of plant nutrient uptake in relation to these processes is essential to understanding the current and future productivity of Arctic ecosystems. 2. In wet sedge meadows located near Churchill, Manitoba, Canada, soil microbial biomass as well as inorganic and organic nutrient pools fluctuate seasonally, with late‐winter peaks followed by declines of these variables during the early stages of soil thaw; however, it is unknown if the dominant plant in this community takes up nitrogen when levels of this nutrient are high but soil temperatures are 0 °C or below. 3. Stable isotope tracing was utilized by injecting 15NH4Cl into soil cores and incubating for 1 or 8 days during spring thaw to determine the short‐term capacity for uptake and transport of inorganic nitrogen into Carex aquatilis (roots, shoots and rhizomes), moss and soil micro‐organisms during this transitional time of year. 4. During three 8‐day experimental trials in April and May 2007, C. aquatilis roots accumulated a substantial amount of the added nitrogen (33.5% increasing to 63.4%), when inorganic nitrogen was readily available in the soil, but declining. A smaller proportion of injected nitrogen was recovered from soil microbes (30% decreasing to 7%), and only trace amounts of injected 15N were measured in plant shoots, shoot bases, rhizomes and mosses (2% or less). 5. Synthesis. Shifting seasonal patterns in northern ecosystems resulting from climate change are likely to alter the progression of events that lead up to the summer growing season. A substantial pool of inorganic nitrogen resides temporarily in the soil at the end of winter, and we have shown here that plants are able to take up nitrogen at this time. Increases in the frequency and temperature highs of late‐winter warming events are likely to trigger early episodes of soil thaw, potentially reducing the capacity of plants to take up this large ephemeral supply of nitrogen in early spring.

Seasonal growth responses of plants and soil microorganisms to additions of nitrogen (N), phosphorus (P) and carbon (C) were examined in goose-grazed and exclosed plots in an Arctic salt marsh. Plants showed strong growth responses to N and NP additions but not to P. Nitrogen levels in the shoots and roots of Puccinellia phryganodes declined as summer progressed. Microbial biomass was low in spring in spite of N and P additions, likely due to C limitation, but values rose in autumn, independent of nutrient treatment, as dissolved organic carbon (DOC) increased. Glucose addition (C source) elicited a transitory increase in microbial biomass. Multiple plant defoliations by geese had a negative effect on microbial biomass, in spite of the presence of DOC and added N and P, possibly because hypersalinity restricted growth. Plants appear to limit soil inputs of C in summer and compete effectively for resources in contrast to autumn, indicating a temporal partitioning of resources.

During winter when the active layer of Arctic and alpine soils is below 0 degrees C, soil microbes are alive but metabolizing slowly, presumably in contact with unfrozen water. This unfrozen water is at the same negative chemical potential as the ice. While both the hydrostatic and the osmotic components of the chemical potential will contribute to this negative value, we argue that the osmotic component (osmotic potential) is the significant contributor. Hence, the soil microorganisms need to be at least halotolerant and psychrotolerant to survive in seasonally frozen soils. The low osmotic potential of unfrozen soil water will lead to the withdrawal of cell water, unless balanced by accumulation of compatible solutes. Many microbes appear to survive this dehydration, since microbial biomass in some situations is high, and rising, in winter. In late winter however, before the soil temperature rises above zero, there can be a considerable decline in soil microbial biomass due to the loss of compatible solutes from viable cells or to cell rupture. This decline may be caused by changes in the physical state of the system, specifically by sudden fluxes of melt water down channels in frozen soil, rapidly raising the chemical potential. The dehydrated cells may be unable to accommodate a rapid rise in osmotic potential so that cell membranes rupture and cells lyse. The exhaustion of soluble substrates released from senescing plant and microbial tissues in autumn and winter may also limit microbial growth, while in addition the rising temperatures may terminate a winter bloom of psychrophiles. Climate change is predicted to cause a decline in plant production in these northern soils, due to summer drought and to an increase in freeze-thaw cycles. Both of these may be expected to reduce soil microbial biomass in late winter. After lysis of microbial cells this biomass provides nutrients for plant growth in early spring. These feedbacks in turn, could affect herbivory and production at higher trophic levels. (C) 2009 Elsevier Ltd. All rights reserved.

We recorded seasonal changes in the total amounts of soluble carbohydrates in shoots of salt- and fresh-water coastal plants at La Pérouse Bay, northern Manitoba, to determine whether adult snow geese and their goslings selected forage rich in soluble carbohydrates during the breeding season. The selection of forage plants in spring and summer by adults and goslings was strongly linked to the presence of high amounts of soluble carbohydrates in tissues: on the order of 100 mg·g–1dry mass. When the content fell as a result of shoot development or leaf senescence, the geese switched to alternative sources of forage. The extent to which individual shoots rich in soluble carbohydrates of the primary freshwater forage species are grazed depends on the local density of breeding geese at the study site, which has fallen in the last decade as a result of the earlier destruction of much of the coastal vegetation by foraging geese.

Summary Plant and microbial nitrogen (N) dynamics were examined in soils of an Arctic salt marsh beneath goose‐grazed swards and in degraded soils. The degraded soils are the outcome of intensive destructive foraging by geese, which results in vegetation loss and near‐irreversible changes in soil properties. The objective of the study was to determine whether vegetation loss led to a decline in microbial activity and a redistribution of N amongst the different soil N pools that potentially could adversely affect plant regrowth. In situ N allocation between plants, microbes and soil was determined based on injection of 15NH4Cl into soil cores; changes in isotopic ratios and N concentrations in the different pools were measured after 24 h. Degraded soils, in contrast to vegetated soils, were characterized by a decline in microbial biomass, reduced microbial 15N excess, reduced rates of gross N immobilization and an increased microbial residency time of 15N. In vegetated soils, both microbes and the forage grass, Puccinellia phryganodes, accumulated 15N such that little remained in the soil abiotic phase after 24 h, unlike in degraded soils. The decline in microbial activity in degraded soils may be linked to a low availability of soil carbon in the absence of plants and to deteriorating abiotic conditions, including the occurrence of hypersalinity in summer. Not all biotic processes respond similarly to the change in ecosystem state. Unlike vascular plant productivity and goose foraging which are absent in degraded soils, soil microbial activity is maintained, albeit at a lower level. In spite of this activity, the greater proportion of 15N in degraded soils is in the abiotic pool rather than in microbial biomass with an increased potential for soil N loss from leaching and soil erosion. Disturbance linked to herbivory often triggers catastrophic shifts in ecosystem properties resulting in vegetation loss and changes in soil biogeochemical cycling that are irreversible, at least on a decadal time scale, and lead to the loss of N and other nutrients required for plant growth. These results clearly illustrate that microbial activity does not compensate for the effects of plant removal on soil N retention.

The extent to which migratory birds that breed in the Arctic and winter in southern biomes rely on residual body stores for reproduction is unresolved. The short arctic summer and the limited availability of food early in the season constrain the time available for successful reproduction. Birds that are able to bring sufficient endogenous reserves to the breeding ground to meet, at least partially, the demands of egg-laying can initiate clutch production soon after arrival, thereby shortening the length of the breeding season and improving the chances of reproductive success. The amount of reserves available will be influenced by body size, the increased energetic and predation costs associated with carrying large stores, distances between staging sites and the location of the breeding grounds within the Arctic. Birds need not fly directly to the breeding grounds from the established temperate staging sites. Extensive feeding by migrants may occur in the Arctic, even within a few kilometres of the breeding sites as the birds track the retreating snowline. Irrespective of their size, birds are thus able to store some resources necessary for egg laying at local or regional scales. It is thus important to make a distinction between local capital and distant capital breeding. The extent to which a bird is characterized as a distant capital, local capital, or an income breeder not only varies between species, but also between individuals and seasons.

Summary Herbivores may initiate small changes to plant–soil systems that trigger positive feedbacks leading to rapid catastrophic shifts in vegetative states, including irreversible changes in soil properties. In the coastal marshes of Hudson and James bays, foraging by increasing numbers of lesser snow geese ( Chen caerulescens caerulescens A.O.U.) has led to loss of vegetation, and exposure and partial erosion of sediment. Multi‐temporal analysis of LANDSAT data has been carried out to detect vegetation change from 1973 to 1999 or later at nine sites in the coastal marshes of these bays where staging and/or breeding geese are present annually. Images were co‐registered, and for each image NDVI (Normalized Differential Vegetation Index) channels were generated. For each location, pairwise normalized differences were calculated between these NDVI images for each successive period defined by the imagery acquisition dates. The resulting secondary NDVI difference images expressed changes in NDVI values for each time interval and yielded three well‐defined classes: water, vegetation decline and no detectable change in vegetation. At the nine widely separated study sites, the intertidal saltmarsh (an ecological sere) has been lost (to a total of 35 000 ha) and an alternative stable state (exposed sediment) established. Similar changes have occurred elsewhere along the 2000‐km coastline where the geese breed or stage. Re‐vegetation of these coastal marshes will take decades because of near‐irreversible changes in soil properties that require erosion and re‐deposition of unconsolidated sediment before large‐scale plant colonization can occur, and because large numbers of geese continue to forage annually producing this dramatic top‐down effect.

During the past 50 years, agricultural practices in Europe and North America have undergone immense change. The development of high-yielding varieties of crops and grasses and their requirement for large amounts of nitrogen and phosphorus fertilizers to sustain yields have revolutionized agriculture. In some countries, larger agricultural units of hundreds of hectares are replacing the small holdings formally held by individual farmers, the outcome of economies of scale, loss of subsidies and the need to remain competitive. In 2001, 43 % of the land area of the European Union (E.U.) was devoted to agriculture. However, in the United Kingdom, Denmark, the Netherlands, Belgium

The current favourable numerical status of most arctic-breeding goose populations conceals an increasing dependence on man-modified habitats for much of the year. Almost all populations are now heavily dependent on agricultural crops when the birds are away from the arctic breeding grounds. We examine the current understanding of the ecology of migration, highlighting the role of hot spots that provide fuelling stations which bridge the gap between the wintering and breeding grounds. Isotopic signatures of eggs indicate nutrients are being flown into the breeding grounds from afar. The susceptibility of geese to disturbance at these stopover sites, many of which are agricultural lands, may lead to reproductive failures. The near-complete loss of natural habitat, even in northern sites, makes the birds captive of agricultural policy. Barnacle Geese Branta leucopsis staging on managed grassland on their spring stopover accumulate more fat but less protein compared to traditional sites, and there is evidence of lower breeding success for individuals feeding on cultivated grass. This population, breeding on Spitsbergen, has been closely followed during a phase of population increase over the past thirty years. We show that although locally on the breeding grounds density-dependent effects have been confirmed (lower reproductive output, enhanced emigration) new colonies are still arising, and there has been no slowing of overall growth of the population. Worldwide, the most spectacular response to agricultural change is that of the Lesser Snow Goose Anser caerulescens cuerulescens. The populations have become so numerous that their spring grubbing activities are having a deleterious impact on arctic wetlands where they breed. It would be erroneous to generalise this example to conclude all long-distance migrating geese should be reduced. Current management polices are insufficiently grounded in basic research on the interaction of geese and their food resources which must include experiments in view of impending climate change. We advocate a vigorous intensification of individual-based research programmes.

Microbial activity is known to continue during the winter months in cold alpine and Arctic soils often resulting in high microbial biomass. Complex soil nutrient dynamics characterize the transition when soil temperatures approach and exceed 0°C in spring. At the time of this transition in alphine soils microbial biomass declines dramatically together with soil pools of available nutrients. This pattern of change characterizes alpine soils at the winter–spring transition but whether a similar pattern occurs in Arctic soils, which are colder, is unclear. In this study amounts of microbial biomass and the availability of carbon (C), nitrogen (N) and phosphorus (P) for microbial and plant growth in wet peaty soils of an Arctic sedge meadow have been determined across the winter–spring boundary. The objective was to determine the likely causes of the decline in microbial biomass in relation to temperature change and nutrient availability. The pattern of soil temperature at depths of 5–15cm can be divided into three phases: below −10°C in late winter, from −7 to 0°C for 7 weeks during a period of freeze–thaw cycles and above 0°C in early spring. Peak microbial biomass and nutrient availability occurred early in the freeze–thaw phase. Subsequently, a steady decrease in inorganic N occurred, so that when soil temperatures rose above 0°C, pools of inorganic nutrients in soils were very low. In contrast, amounts of microbial C and soluble organic C and N remained high until the end of the period of freeze–thaw cycles, when a sudden collapse occurred in soluble organic C and N and in phosphatase activity, followed by a crash in microbial biomass just prior to soil temperatures rising consistently above 0°C. Following this, there was no large pulse of available nutrients, implying that competition for nutrients from roots results in the collapse of the microbial pool.

Since the 1970s, a breeding colony of lesser snow geese (Chen caerulescens caerulescens L.) at La Perouse Bay, Manitoba, has grown 8% annually. This increase has led to significant loss of plant cover in all major salt- and freshwater coastal habitats between 1976 and 1997. A series of transects established in 1976 was resurveyed in 1997. Exposed sediment, extent and type of vegetative cover, and aquatic areas were recorded along transects using a classification of 12 a priori classes. Five regions within the colony were identified, and changes in vegetation cover differed among these and depended on unique combinations of vegetation class and year. Grubbing by geese has led to loss of graminoid plants, especially in intertidal and supratidal marshes. Exposed sediments have largely replaced previously vegetated areas since 1976. Species characteristic of disturbed sites have colonized exposed sediment with the most abundant species varying according to soil conditions. In intertidal marshes, willow cover declined in association with the development of hypersalinity after loss of the graminoid mat, but willow cover increased at the base of well-drained beach ridges and in a river delta with ample winter snow accumulation and freshwater flow in spring that protected ground vegetation. Most of the expected successional trends associated with isostatic uplift and changes in soil organic matter failed to occur because of intense goose foraging throughout the 20 years. The likelihood of sustained recovery of plant communities in the immediate coastal zone is very low, as long as goose numbers continue to increase. Indirect effects of vegetation loss (e.g., hypersalinity) and subsequent erosion of exposed sediments following grubbing will delay plant colonization and retard succession.